Jet pump lift system for producing hydrocarbon fluids

ABSTRACT

A jet pump lift system for use with a tubing disposed in a casing includes a jet pump installed in the tubing; a one way valve for communicating a power fluid into the jet pump; and a safety valve configured to block fluid communication through the tubing and disposed above the jet pump.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention generally relate to artificiallylifting fluid from a wellbore. More particularly, embodiments of thepresent invention relate to artificially lifting fluid from a wellboreusing a jet pump lift system.

Description of the Related Art

To obtain hydrocarbon fluids from an earth formation, a wellbore isdrilled into the earth to intersect an area of interest within aformation. The wellbore may then be “completed” by inserting casingwithin the wellbore and setting the casing therein using cement. In thealternative, the wellbore may remain uncased (an “open hole wellbore”),or may become only partially cased. Regardless of the form of thewellbore, production tubing is typically run into the wellbore primarilyto convey production fluid (e.g., hydrocarbon fluid, which may alsoinclude water) from the area of interest within the wellbore to thesurface of the wellbore.

Often, pressure within the wellbore is insufficient to cause theproduction fluid to naturally rise through the production tubing to thesurface of the wellbore. Thus, to carry the production fluid from thearea of interest within the wellbore to the surface of the wellbore,artificial lift means is sometimes necessary.

Some artificially-lifted wells are equipped with sucker rod liftingsystems. Sucker rod lifting systems generally include a surface drivemechanism, a sucker rod string, and a downhole positive displacementpump. Fluid is brought to the surface of the wellbore by pumping actionof the downhole pump, as dictated by the drive mechanism attached to therod string.

One type of sucker rod lifting system is a rotary positive displacementpump, typically termed a progressive cavity pump (“PCP”). Theprogressive cavity pump lifts production fluid by a rotor disposedwithin a stator. The rotor rotates relative to the stator by use of asucker rod string.

An additional type of sucker rod lifting system is a rod lift system,with which fluid is brought to the surface of the wellbore byreciprocating pumping action of the drive mechanism attached to the rodstring. Reciprocating pumping action moves a traveling valve on thepositive displacement pump, loading it on the down-stroke of the rodstring and lifting fluid to the surface on the up-stroke of the rodstring.

Sucker rod lifting systems include several moving mechanical components.Specifically, the rod strings of sucker rod lifting systems must bereciprocated or rotated to operate the lifting systems. In someapplications, the moving parts are disadvantageous. When a subsurfacesafety valve is employed within the wellbore, such as within an offshorewell, a sucker rod string cannot be placed through the subsurface safetyvalve. Additionally, moving parts are susceptible to failure or damage,potentially causing the sucker rod lifting systems to become inoperable.

An alternative lift system involves using a jet pump. As shown in FIG.1, a production tubing 10 having a jet pump 20 is installed in a casing15. The jet pump 20 includes a nozzle section, a venturi section, andinlets ports in fluid communication with the venturi section. A portedsub 22 fluidly connects the bottom of the venturi section with theannular area between the tubing 10 and the casing 15. Production fluidflowing up the tubing 10 can flow into the venturi section via the inletports.

In operation, power fluid is directed down the tubing 10 toward thenozzle section of the jet pump 20. Power fluid exiting the nozzlesection is directed through the venturi section. As the power fluidpasses from the nozzle section to the venturi section, production fluidis drawn into the venturi section via the inlet ports. The combinedpower fluid and production fluid leave the venturi section via theported sub 22 and enter the annular area, where the combined fluids flowupward to the surface.

In many of these operations, a safety valve is attached to a landingnipple 23 disposed below the jet pump 20. The safety valve serves as asafety barrier for both the tubing 10 and the casing 15 by blockingcommunication through the bore of the tubing 10. In some instances, thejet pump is installed at depths of 8,000 ft. or more. Because the safetyvalve is below the jet pump, the safety valve must be rated for use atthese depths. The safety valves required for these depths are usuallymuch more expensive than safety valves rated for use at shallowerdepths; in some instances, more than double or triple the costs. Thecost associated with control lines for operating the safety valves alsoincrease with depth.

There is, therefore a need for an improved lift system for producinghydrocarbon fluids. There is also need for a lift system that allows asafety valve to be installed above a jet pump.

SUMMARY OF THE INVENTION

In one embodiment, a jet pump lift system for use with a tubing disposedin a casing includes a jet pump installed in the tubing; a one way valvefor communicating a power fluid into the jet pump; and a safety valveconfigured to block fluid communication through the tubing and disposedabove the jet pump.

In another embodiment, a method of producing hydrocarbon fluids includesinstalling a jet pump in a production tubular; maintaining a safetyvalve located above the jet pump in an open position; supplying a powerfluid through a one way valve and into the jet pump; urging a productionfluid into the jet pump; and flowing the production fluid and the powerfluid past the safety valve.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 shows a prior art artificial lift system using a jet pump.

FIG. 2 shows an exemplary artificial lift system using a jet pump and aone way valve.

FIG. 2A is an enlarged partial view of the lift system of FIG. 2.

FIG. 3 illustrates an exemplary embodiment of a one way valve.

DETAILED DESCRIPTION

Embodiments of the present disclosure relate to an artificial liftsystem using a jet pump and a one-way valve for fluid communicationbetween the jet pump and a power fluid source. In one aspect, the jetpump driven system advantageously allows a safety valve to be installedabove the jet pump.

FIG. 2 shows an exemplary artificial lift system for producing ahydrocarbon fluid. FIG. 2A is an enlarged partial view of FIG. 2. A jetpump 120 is installed in a production tubing 110 disposed in a casing115. A packer 117 blocks the annular area between the tubing 110 and thecasing 115 below the jet pump 120.

The jet pump 120 includes a tubular housing 121 having an inlet locatedat a lower end and an outlet located at an upper end. The outer surfaceof the two ends of the tubular housing 121 sealingly engages the innersurface of the bore of the tubing 110. In this respect, production fluidflowing up the bore is directed into the inlet of the housing 121. Inone embodiment, the ends may be sealed using one or more sealing members111 such as o-rings and chevron seals.

An annular chamber 118 is defined between the two sealed ends andbetween the tubing 110 and the housing 121 of the jet pump 120. A oneway valve 160 is used to control fluid communication between the annularchamber 118 and the annular area 113 between the tubing 110 and thecasing 115. The one way valve 160 is configured to allow fluid in theannular area 113 to flow into the annular chamber 118. In this respect,the one way valve 160 prevents pressure increases, such as a blow-outcondition, from being communicated into the casing 115. An exemplary oneway valve is a check valve. It is contemplated that a single or aplurality of one way valves may be used to communication fluid into theannular chamber 118. In one example, the one way valve 160 can belocated at any location between the jet pump and the power fluid source.In another example, the one way valve 160 is located below the valve180, as shown in FIG. 2. In yet another example, the one way valve 160is located at a depth between 6,000 ft. and 30,000 ft., such as between8,000 ft. and 20,000 ft. In a further example, the one way valve islocated at a depth between 6,000 ft. and the depth of perforation.

In one embodiment, the jet pump 120 is installed in a tubing 110 havinga side pocket mandrel 114, as disclosed in U.S. Pat. No. 7,228,909,which patent is incorporated by reference, in particular, FIGS. 1, 2A,2B, 3, and 5, and the corresponding description.

FIG. 3 illustrate an exemplary embodiment of a one way valve 335suitable for use with a side pocket of the tubing. The one way valve 335includes a tubular body 305 having a generally longitudinal central bore336 therethrough and having an upper end 301 and a lower end 302. Thelower end 302 includes an outlet port 313 for ejecting fluid from thebore 336, and the upper end 301 includes a connector for connecting theone way valve to a latching mechanism for retrieval. The tubular body305 includes two inlet ports 331A, 331B fluidly connecting the centralbore 336 to the outside of the one way valve 335. Seal assemblies 328,329 form a seal path for the fluid to enter the inlet ports 331A, 331B.A first ball and seat mechanism 340 is used to control fluidcommunication between the inlet ports 331A, 331B and the bore 336. Whenthe fluid outside the one way valve 335 reaches a predetermined level,the ball will be urged away from the seat, thereby allowing fluid, suchas power fluid P, to flow into the bore 336. A second ball and seatmechanism 350 is disposed in the body 305 between the first ball andseat mechanism 340 and the outlet port 313. The second ball and seatmechanism 350 allows fluid flow from the inlet ports 331A, 331B to theoutlet port 350, but does not allow fluid flow in the oppositedirection.

Referring back to FIGS. 2 and 2A, the jet pump 120 includes a nozzlesection 122 spaced apart from a venturi section 124. The spaced area 125between the nozzle section 122 and the venturi section 124 fluidlycommunicates with the bore of housing 121. This arrangement allows fluidflowing through the inlet of the housing 121 to flow toward the venturisection 124. A side port 126 formed in the tubular housing 121 providesfluid communication between the annular chamber 118 and the interior ofthe nozzle section 122. The nozzle section 122 includes a throat 128having an inwardly tapered portion that increases the velocity of thepower fluid flowing out of the nozzle section 122. The venturi section124 is configured to receive power fluid from the nozzle section 122 andthe production fluid. The venturi section 124 includes an outwardlytapered portion 129 that increases the pressure of the combined fluidsflowing out of the venturi section 124 while decreasing the velocity ofthe combined fluids. Exemplary power fluids include water, oil,hydrocarbon, and combinations thereof.

A safety valve 180 is installed in the tubing 110 and above the jet pump120. In one embodiment, the safety valve 180 includes a flapper 181movable between an open position and a closed position. The flapper 181is operated by a flow tube 182 controlled by a control line. As shown,the flapper 181 is maintained in the open position by the flow tube 182.To close the flapper 181, pressure is supplied through the control lineto move the flow tube 182 upward, thereby freeing the flapper 181 topivot into the bore of the tubing 110 to block fluid communicationthrough the bore. To open the flapper 181, pressure is supplied throughthe control line to move the flow tube 182 downward, thereby pivotingthe flapper 181 away from the bore to open fluid communication throughthe bore.

In operation, production fluid 141 in the tubing 110 flows upward andenters the jet pump 120 via the inlet of the tubular housing 121. Powerfluid 142 is supplied down the annular area 113 between the tubing 110and the casing 115 toward the jet pump 120. The power fluid 142 thenpasses through the one way valve 160 and enters the annular chamber 118.The power fluid 142 flows through the side port 126 toward the throat128 of the nozzle section 122. As the power fluid 142 is forced throughthe throat 128, the velocity of the power fluid 142 is increased. Thepower fluid 142 exiting the throat 128 passes through the spaced area125 and enters the venturi section 124. As the power fluid passes fromthe nozzle section 122 to the venturi section 124, production fluid 141in the spaced area 125 is drawn into the venturi section 124. Thecombined fluids 141, 142 then flow through the outwardly tapered portion129, where the velocity of the combined fluids is decreased and thepressure is increased. The combined fluids 141, 142 flows out of the jetpump 120 and up the tubing 110. The flapper 181 is retained in the openposition to allow the combined fluids 141, 142 to flow to the surface.

As discussed, embodiments of the jet pump lift system advantageouslyallow the safety valve to be installed above the jet pump. Because theone way valve prevents fluid communication from the tubing 110 intoannular area 113 with the casing 115, the safety valve only needs toblock fluid communication up the tubing 110. In one example, the safetyvalve is located at 3,000 ft. or above, such as between 200 ft. and2,500 ft., between 1,000 ft. and 2,000 ft., and 2,000 ft. or above.Safety valves rated for these depths cost substantially less than safetyvalves rated for much lower depths, such as between 8,000 ft. and 20,000ft.

Any directional terms used in the description above are merelyillustrative, for example, the terms “upward”, “downward”, etc., and notlimiting. It is understood that the production tubing described above isusable within any orientation of wellbore, including but not limited toa vertical, horizontal, directionally-drilled, or lateral wellbore.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A jet pump lift system for use with a tubing disposed in a casing,comprising: a jet pump installed in the tubing; a one way valve forcommunicating a power fluid into the jet pump; and a safety valveconfigured to block fluid communication through the tubing and disposedabove the jet pump.
 2. The system of claim 1, wherein the one way valvecomprises a check valve.
 3. The system of claim 1, wherein the safetyvalve comprises a flapper valve.
 4. The system of claim 1, wherein theone way valve allows fluid communication from an annular area betweenthe tubing and the casing to the jet pump.
 5. The system of claim 1,wherein the one way valve is positioned below the safety valve.
 6. Thesystem of claim 1, wherein the safety valve is positioned at a depth of3,000 ft. or less.
 7. The system of claim 6, wherein the one way valveis positioned at a depth of 6,000 ft. or more.
 8. The system of claim 1,wherein the one way valve is positioned at a depth of 6,000 ft. or more.9. The system of claim 1, further comprising an annular packer locatedbelow the one way valve.
 10. The system of claim 1, wherein the one wayvalve is installed in a side pocket of the tubing.
 11. A method ofproducing hydrocarbon fluids, comprising; installing a jet pump in aproduction tubular; maintaining a safety valve located above the jetpump in an open position; supplying a power fluid through a one wayvalve and into the jet pump; urging a production fluid into the jetpump; and flowing the production fluid and the power fluid past thesafety valve.
 12. The method of claim 11, wherein the production tubularis disposed in a casing, and the power fluid is supplied down an annulararea between the production tubular and the casing.
 13. The method ofclaim 12, wherein the one way valve controls power fluid flow into theproduction tubular.
 14. The method of claim 11, wherein the power fluidflows into the jet pump via a side port.
 15. The method of claim 11,wherein the safety valve comprises a flapper valve.
 16. The method ofclaim 11, wherein the one way valve comprises a check valve.
 17. Themethod of claim 11, wherein the safety valve is located a depth of 3,000ft. or less.